Photographic printing device



Jan. 20, 1942. J. T. CAMPBELL 2,270,573

PHOTOGRAPHIC PRINTING DEVICE Filed'Feb. 4, 1941 2 Sheets-Sheet l L 0 M L I g lNVENig/ll Ma 57 ATTORNEY Jan. 20, 1942. J, CAMPBELL 2,270,578

PHOIOGRAPHIC PRINTING DEVICE Filed Feb. 4, 1941 2 Sheets-Sheet 2 INVENTOR' ATTORNEY Patented Jan. 20, 1942 UNITED STATES PATENT OFFICE PHOTOGRAPHIC PRINTING DEVICE James '1. Campbell, Highland Park, Mich.

Application February 4, 1941, Serial No. 377,357

16 Claims.

This invention relates to vacuum printing mechanisms of the type employed for photographically printing upon a sensitized plate from a suitable negative disposed in close contact thereto, and utilizing an intense light source for the printing operation.

Heretofore printing mechanisms of this type have been employed utilizing a light source exterior to the printing mechanism.

It is the object herein to provide a lighting mechanism built within and forming a part of the printing device.

It is the object herein to provide a light, enclosing reflector hood whereby the full eifect of the light is brought to bear upon the printing operation, eliminating at the same time the usual disturbing glare heretofore experienced. Furthermore by said reflector hood enclosure the light is directional and is not disturbed or lost throughout a room, but is concentrated uniformly upon the printing surface. By virtue of this arrangement the printing time has been reduced 50 per cent.

It is the further object hereof to provide a compact printing unit with a yielding blanket frame disposed thereon, having a circumferential air sealing elastic moulding adapted to engage a glass frame, the latter being secured to said hood, which hinged along one of its edges, provides a manually operable closure.

It is the further object of this invention to provide a novel resiliently mounted latching mechanism guaranteeing a positive closure of the hood and glass frame, permitting an air sealing contact to be made between said glass frame and blanket. This latch device eliminates the use, adjustment, and repair of cumbersome clamps heretofore required for maintaining the frames in proper air sealed juxtaposition for retaining the negative in close contact with the sensitized plate.

It is the further object hereof to provide a novel printing unit utilizing a substantially high voltage water cooled mercury arc lamp centrally disposed within the top portion of the hood, with a water jacket disposed around said lamp, and with means in said unit for conducting water through said jacket.

Heretofore the life of lamps of this type have been short due to the fact that the water supply is turned off at the same time that the light is turned off.

The invention includes an auxiliary reservoir in the water line within said printing device which will store a quantity of water under a pressure. Consequently when the main supply is turned off with the light, the water from the reservoir will continue to circulate through the lamp jacket for further cooling said lamp.

It is the further object of this invention to provide a printing device which is compact and requires only one-half the floor space heretofore required.

By attaining the objects hereinabove set out, a vacuum printing device is provided which is characterized by a substantial ease of operation.

Other objects are obtained by the various arrangements of element and combinations thereof hereinafter described in detail and illustrated in the accompanying drawings in which:

Figure 1 is a front elevational view of the printer with the reflector hood up.

Figure 2 is a similar fragmentary view of the hood down.

Figure 3 is a side elevational view of the printer; and

Figure 4 is a diagrammatic view of the interior of the printing device.

The above illustrations are merely preferable embodiments of the invention, it being expressly understood that the invention is not limited thereby.

In the drawings the printing device consists of a hollow body member II with legs I2, and having horizontally disposed upon said body a blanket frame l3.

A yieldable rubber or elastic blanket member I4 is supported upon frame l3 and is provided with a raised circumferential moulding l5.

A hood IS with interior reflecting surfaces I6 is provided for said body member ll hingedly secured thereto at points and adapted to be opened and closed with respect to the blanket member M.

A glass frame I8 is secured to said reflector hood and is movable therewith for establishing an air sealing contact with the moulding [5 of blanket l4. Consequently the space therebetween may be evacuated in the manner hereinafter described.

For printing, a suitable sensitized plate is placed upon blanket M with the negative sought to be reproduced placed upon the top thereof. It is well known in the art that to obtain the best results the negative must be brought into close contact with the sensitized plate. This is accomplished with the glass frame l8 in air sealing contact with moulding l5. Connection is then made with a vacuum pump l9 by a flexible conduit 20 terminating in the opening 2| in the top surface of the rubber blanket Hi. When the switch 22 shown in Figure l is actuated the vacuum pump I9 is turned on and the space between the blanket l4 and the glass 15 is promptly evacuated, causing the former to rise against the latter, thereby a perfect contact is made between said negative and sensitized plate,

The printing operation is completed by the application of a bright light, disposed within the hood member l6 and designated at 23, with electrical connections 24.

In applicants preferable embodiment a 1,000 watt mercury are water cooled lamp 23 is employed, as diagrammatically shown in Figure 4, with a water jacket 25 disposed therearound, it being essential for the successful operation of said lamp that the same be placed in a moving stream of water for continuous cooling throughout the illumination thereof.

Water enters the jacket 25 through a hose 26 in the end thereof and leaves at the other end whence it escapes by any suitable connection with a drain.

The water supply, as shown in Figure 4, from a water main is controlled by a solenoid valve 21, which is electrically actuated by the control switch 28, a suitable strainer 29 being interposed as shown in Figure 4.

A fluid pressure switch 30 is interposed for fluid connection with the water conduit 26, whereby when a certain predetermined pressure is reached, such as preferably lbs. per square inch, said switch makes the necessary electrical contact for lighting the lamp 23.

Consequently with the water turned off or if the water pressure is under the predetermined pressure required for adequate cooling, the lamp will not operate. In the event of any failure in the water supply, it will be seen that the lamp is automatically turned off by switch 30.

In order to increase the life of lamp 23 a water reservoir 3| is disposed in the fluid line 26, whereby during operation of the lamp, fluid is forced therein and a pressure established within the space indicated at 32 in Figure 4.

The lamp is manually turned off by actuating the switch 28, which controls the solenoid valve 21, in turn operating the pressure switch 30 through the fluid conduit 26.

The lamp still being hot, additional cooling thereof is provided by the water supply under pressure from the reservoir 3|. This additional flow of water is automatic and is found to considerably prolong the life of the lamp.

It will be noted that the front panel of the printing mechanism I l is provided with a vacuum gage 33 for visibly determining the extent of vacuum available for the printing operation as heretofore described.

Furthermore a running time meter 34 is provisioned as shown in Figure 1 for measuring the life of the lamp 23.

A timing switch 35 is also provided adapted to automatically operate the lamp for any given predetermined period of time.

As hereinabove mentioned novel means are employed as shown in Figure 3 for guaranteeing an air tight seal between the glass frame l8 and the moulding I 5 of blanket member I4.

Link 36 pivotally joined to the reflector hood at 31, is also joined to the lever 38 which is centrally pivoted at 39. A connecting link 40 loosely joined to the end of lever 38 at point 4|, is secured at its other end to the coiled spring 42 the latter being anchored near the base of the printer housing H at point 43.

A suitable stop 44 adapted to cooperate with lever 38 is provided for limiting the upward movement of the hood 16, said movement being facilitated by the resilient action of spring 42 upon the lever 38. Closing tightly the hood I6 by handle 45 is also facilitated by spring 42 after said reflector hood is substantially closed, because in this position point 46 of link 36 is above the center line of the glass frame l8. Consequently the lever 38 resiliently closes said hood with a forcing action thereby guaranteeing an air tight seal between moulding l5 and the glass IS.

A trap door 41 is formed within the front surface of hood [6 horizontally hinged thereto at 48 and manually raisable by handle 49. With the hood down in printing position as in Figure 2 the trap door may be opened Without disturbing said hood or glass frame l8. This door is advantageous for the purpose of manually masking one or more of a plurality of prints being made where, for instance, their printing requires less light in duration of time than others on the blanket l4; and it is desirous to cover them up. This is a substantial time saver, because it eliminates the unnecessary operation of removing some of the prints before continuing with the rest.

Referring to Figure 4 the relay 50 is joined to the fluid pressure switch 30 through electrical connection 5|, with fluid conduit 30 joining the fluid line 26.

A fuse box 52 with switch 53 provides the necessary outlets 54 for electrically connecting the solenoid valve 27 in the water cooling system, manually controllable by switch 28.

Connection with transformer 55, of the leakage-reactance type for obtaining preferably herein a voltage of 840 volts for lamp 23, is made from said relay 5!] via electrical connections 58. Outlets 24 from the high voltage side of transformer 55 electrically connects the mercury arc lamp 23.

It will be noted that the printer housing II has slidably disposed therein a draw 51 with handles 58 therefor.

It will be noted that due to the cooled light there is practically no expansion of the negative or sensitized metal plate during the printing process. This eliminates any creeping of the image which under a hot light is quite apt to give a fuzzy print with less opacity on the extreme outer margins. Or on the other hand, this creeping may throw a print out of register in color work.

Having described my invention reference should now be had to the claims which follow for determining the scope thereof,

I claim:

1. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame, a hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, Water cooling means for said illuminating means, water pressure actuated means for establishing electrical contact to said illuminating means at a predetermined water pressure, and a water reservoir joined to said cooling means for providing additional cooling fluid when the main water supply is off.

2. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame, a reflector hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminating means, a fluid conduit joined thereto and adapted for connection to a water source, a water pressure switch for said illuminating means, a control for said water supply, a water reservoir in communication with said conduit and adapted to establish a supply of water under pressure therein, whereby additional cooling fluid is provided after the water supply is cut off. 1

3. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame hinged upon said supporting member, illuminating means for said blanket member, water cooling means for said illuminating means, a water pressure actuated switch for said illuminating means, and a water reservoir in communication with said cooling means to provide auxiliary fluid under pressure for said 0001- ing means after the water supply is cut ofi.

4. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame, a reflector hood for said blanket member hinged to said supporting member and carrying saidglass frame, illuminating means disposed within the top of and carried by said hood, with suitable electrical connections therefor on the top of said hood, a hollow water cooling jacket surrounding said illuminating means, and water supply conduits disposed through thesides of said hood joining the opposite ends of said jacket for conducting water through the same.

5. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating airsealing glass frame, a reflector hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within the top of and carried by said hood, a hollow water cooling jacket surrounding said illuminating means, and water supply conduits disposed through the sides of said hood joining the opposite ends of said jacket for conducting water through the same, and water pressure actuate means communicating with said cooling jacket for establishing electrical contact to said illuminating means at a predetermined water pressure.

6. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame, a hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminatingmeans, water pressure actuated means for establishing electrical contact to said illuminating means at a predetermined water pressure, a water reservoir joined to said cooling means for providing additional cooling fluid when the main water supply is off, and resilient means joining said hood and supporting member for facilitating the manual elevation thereof, and for resiliently closing said hood with respect to said blanket member.

'7. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame, a hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminating means, water pressure actuated means for establishing electrical contact to said illuminating means at a predetermined water pressure, a water reservoir joined to said cooling means for providing additional cooling fluid when the main water supply is off, a lever centrally pivoted to said supporting member, an interconnecting link on the end of said lever pivotally joined to said hood, and resilient means anchored to said supporting member and secured to the other end of said lever, whereby a resilient force is applied to facilitate closing said hood and establishing an air-tight seal between the glass frame and blanket member.

8. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame, a hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminating means, water pressure actuated means for establishing electrical contact to said illuminating means at a predetermined water pressure, a water reservoir joined to said cooling means for providing additional cooling fluid when the main water supply is off, a lever centrally pivoted to said supporting member, an interconnecting link on one end of said lever pivotally joined to said hood, the pivotal connection between said lever and link being above the pivotal connection of said hood when the latter is partially closed, and resilient means anchored to said supporting member and secured to the other end of said lever, whereby a resilient force is applied to facilitate closing said hood and establishing an air-tight seal between the glass frame and blanket member.

9. In a vacuum printing device, the combination, a yielding blanket member, a cooperating air-sealing glass frame, a hood for said blanket member, illuminating means disposed within and carried by said hood, a water jacket for said illuminating means, a water switch for actuating said illuminating means at a predetermined pressure, and a water reservoir joined to said jacket to supply additional cooling after the main water supply is cut off.

10. In a vacuum printing device, the combination, a supporting member, a yielding blanket member, a cooperating air-sealing glass frame, a reflector hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminating means, a fluid conduit joined thereto and adapted for connection to a water source, a water pressure switch joined to said water cooling means for actuating said illuminating means, a water reservoir in communication with said conduit and adapted to establish a supply of water under pressure therein, whereby additional cooling fluid is provided after the water supply is cut off.

11. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, an elastic beading upon said support circumferentially disposed around said blanket member, an air-sealing glass frame hinged upon said supporting member adapted to cooperatively engage said beading, llluminating means for said blanket member, water cooling means for said illuminating means, a water pressure actuated switch for said illuminating means, and a water reservoir in communication with said cooling means to provide auxiliary fluid under pressure for said cooling means after the water supply is cut off.

12. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating airsealing glass frame hinged upon said supporting member, illuminating means for said blanket member, water cooling means for said illuminating means, and a water reservoir in communication with said cooling means to provide auxiliary fluid under pressure for said cooling means after the water supply is cut off.

13. In a vacuum printing device, a yielding blanket member, a cooperating air-sealing glass frame, illuminating means for said blanket member, water cooling means for said illuminating means, and a water reservoir in communication with said cooling means to provide auxiliary fluid under pressure for said cooling means after the water supply is cut off.

14. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating air-sealing glass frame hinged upon said supporting member, illuminating means for said blanket member, water cooling means for said illuminating means, a water pressure actuated switch for said illuminating means, a water reservoir in communication with said cooling means to provide auxiliary fluid under pressure for said cooling means after the water supply is cut oil, and

vacuum producing means communicating with the upper surface of said blanket member.

15. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating airsealing glass frame, a reflector hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminating means. a fluid conduit joined thereto and adapted for connection to a water source, a water pressure switch for said illuminating means, a water reservoir in communication with said conduit and adapted to establish a supply of water under pressure therein, whereby additional cooling fluid is provided after the water supply is out 01f, and vacuum producing means communicating with the upper surface of said blanket member.

16. In a vacuum printing device, the combination, a supporting member, a yielding blanket member disposed thereon, a cooperating airsealing glass frame, a hood for said blanket member hinged to said supporting member and carrying said glass frame, illuminating means disposed within and carried by said hood, water cooling means for said illuminating means, water pressure actuated means for establishing electrical contact to said illuminating means at a predetermined water pressure, a water reservoir joined to said cooling means for providing additional cooling fluid when the main water supply is oif, and vacuum producing means communicating with the upper surface of said blanket member.

JAMES T. CAMPBELL. 

